#include <stdio.h>
#include <stdlib.h>
#define MAXOP 100
#define NUMBER '0'
int getop(char []);
void push (double);
double pop(void);


int main()
{
	int type;
	double op2;
	char s[MAXOP];

	while ((type = getop(s)) != EOF) {
			switch (type) {
			case NUMBER:
			    push(atof(s));
			    break;
			case '+':
			    push(pop() + pop());
			    break;
			case'*':
			     push(pop() * pop());
		         break;	
			case'-':
			    op2 = pop();
			    push(pop() - op2);
			    break;
			case'/':
			    op2 = pop();
			if (op2 != 0.0 )
			push(pop() / op2);
			else
			    printf("error:zero divisor\n");
			break;
			case '\n':

			    printf("\t%.8\n", pop());
				break;
			default:
				  printf("error:unknown command %s\n", s);
				  break;
			}
	}
return 0;
}